Buffer overflow in Microsoft 365 Copilot
CVE-2026-50387
Stack-based buffer overflow in Windows GDI allows an authorized attacker to elevate privileges locally.
Vulnerability class: Buffer Overflow
EPSS: 0.003 (25.8th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
Affected products
- Microsoft 365_copilot
- Microsoft Microsoft_365
- Microsoft Office 365 For Mac — versions 1.0.0
- Microsoft Office For Android — versions 16.0.1
- Microsoft Office Ltsc For Mac 2021 — versions 16.0.1
- Microsoft Office Ltsc For Mac 2024 — versions 16.0.0
- Microsoft Office_2021
- Microsoft Office_2024
- Microsoft Windows_10_1607
- Microsoft Windows_10_1809
Weakness classification (CWE)
References
- Windows GDI Elevation of Privilege Vulnerability (vendor-advisory, Patch, patch, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-50387?
- CVE-2026-50387 is a high-severity vulnerability in Microsoft 365 Copilot, classified under Stack-based Buffer Overflow. CVSS score: 7.8/10. Published 2026-07-14.
- How severe is CVE-2026-50387?
- High severity. CVSS v3 base score is 7.8 out of 10.